This is a fast-paced story narrated by Leo (15), who has run away from her cousins' house and an obsessive and potentially dangerous uncle, and Finlay a Glasweigan paperboy who stumbles across Leo and becomes her friend. There are occasional extras throughout, an interesting touch, which include for example a newspaper report, diary entries from Leo's uncle, e-mail from a cousin. From the very beginning, the reader is drawn in, wondering what Leo is escaping from and what she's hoping to find. The story deals with hard-hitting themes of parental loss, mental illness, and the perils of teenage homelessness and yet, whilst quite gritty, it avoids being heavy going. Leo and Fin's mad friends provide Leo with a home and considerable kindness and for the reader, both interest and humour. Running on the cracks is a fairly quick read for the younger teenager, written in short chapters with a fast punchy style, with an urgent credible storyline for early teens, and an ending that is hopeful yet realistic. I would certainly recommend this for young people who enjoy the contemporary settings and issues of Jacqueline Wilson's books, and I applaud Julia Donaldson's first foray into books for older readers. A definite success.